When dealing with syringes, generally two modes of concern, i.e. spills and cross contamination should be considered. The first, being of greatest concern in oncology and other hazardous drug handling, deals with spills which may occur at a luer connecting interface, e.g. at the connecting end of a syringe. As most often provided, each syringe has an open orifice within a luer-lock interface. When that interface is inadvertently opened, resulting drug spills are often considered very dangerous.
In broader scope, methods related to the instant invention comprise processes for using connectors which are affixed via a friction fit. Examples of such connectors are bag spikes and luer-lock fittings. The desirability for increased safety for such connectors has been well established by spikes which have been inadvertently pulled from a bag and by syringe affixed luer fittings which have been twisted free when attempting to disconnect an associated fitting connected in tandem. It is important to note that employing a needleless connector and a dripless needleless connector adapter requires two connectors be placed in tandem forming a common flow path there through. Dangers associated with disengaging the wrong connector are well known in medical art, especially when handling oncology or other hazardous drugs.
Noting that each syringe to connector adapter and connector adapter to needleless connector interconnection is disengaged by rotation in the same direction, it becomes evident that there is a need for some differentiating feature to assure the wrong connection is not disengaged. As it is critical that only the needleless connector/connector adapter interface be disengaged when breaking the flow path, it is commonly taught, through in-servicing, to grasp the connector adapter when performing a disengagement rotation to assure the syringe/connector adapter interconnection remains secure. However, experience has shown that inadvertent rotation of an associated syringe rather than grasping the connector adapter can occur and when stiction (force required to overcome static friction and initiate motion) of the syringe/connector adapter interface is less than stiction of the needleless connector/connector adapter interface. In such a case, the syringe can be resultingly disengaged from the connector adapter providing opportunity for a spill.
An example of a special connector designed for improved securement is the Spinning Spiros® available from ICU Medical, San Diego, Calif. Once secured to a site, the Spinning Spiros is designed to physically detach connection between parts which are disposed to be radially displaced to free the Spiros.
The second mode of concern is residue which is distributed across the inner wall of a syringe barrel by bidirectional displacement of an associated plunger. Of course, when a plunger is displaced to dispense fluid from the syringe, any material not wiped from the inner wall of the barrel becomes residue which is available to the open proximal end of the syringe. Similarly, any contamination on the barrel wall proximally disposed relative to the plunger of the syringe which is not wiped when the plunger is proximally displaced is left to contaminate fluid within the barrel which is distally disposed to the plunger.
An example of a special device which is commercially available for addressing this problem is EquaShield® made and distributed by EquaShield Medical, Ltd. The EquaShield is designed to replace fluid drawn from a vial or other liquid source with fluid originally disposed in the proximal end of a closed syringe barrel to obviate cross contamination across a plunger.
Other cross contamination barriers for medical syringes are known in the medical art. Examples of art disclosing such barriers are found in U.S. Pat. No. 5,976,112 (now abandoned) which was filed by Henry Walker Lyza, Jr (Lyza) and allowed. Nov. 2, 1999 and titled INJECTOR SYRINGE. In addition, a U.S. Patent Application 2007/0106226 filed by Perry W. Croll, et al. (Croll), and titled SYRINGE WITH INTERNAL SLEEVE filed Nov. 9, 2005, and the U.S. Patent Application cited as Thorne 963, supra, provide other related art.
Each of the examples cited supra disclose a tube of substantially constant diameter and thickness between a distal end portion and a rolled proximal end part. As well, all disclose that material used in such tubes is sufficiently elastic to be wrapped around syringe flanges such that the rolled proximal end part can form a barrier about the barrel of the syringe.
In practice, it has been found that wear during use and storage, changes in material due to aging and sterilization procedures and stress associated with stretching such material about flanges of an associated syringe can result in material failure in tubes of substantially constant diameter and thickness resultingly uncovering parts of the associated syringe to undesirable external exposure. In particular, it has also been found that shearing along edges of plunger rods (and more particularly along plunger rod edges with parting lines) associated with displacement of syringe plungers at the commonly provided retention ring of a conventional syringe is a source of material tearing and resulting malfunction.
Such external exposure can have serious consequences because exposure to sources external to the syringe can contaminate the inside of a syringe barrel with material which may be communicated into a syringe delivery chamber distal to a syringe plunger. In like manner, if material in the distal chamber of a syringe is hazardous and is communicated into a portion of the barrel of the syringe proximal to the syringe plunger, such can also lead to serious consequences. For these reasons, it is critical that robustness of the material assures that such failures do not occur.
Further, syringe flanges provide a digital interface which often involve gloved hands. As such that interface, as part of the instant invention, involves a portion of a cross contamination tube disposed about the flanges presenting a surface which is characteristic of material used in the tube. Care must be taken that such an interface is not too slick, not allergenic and preferably presents an improved (e.g. skid resistant) digital contact surface.